This invention pertains to closures embodying tamperproof or tamper-indicating structures and more particularly it relates to a tamperproof structure for a press-on or snap-on type of closure member which incorporates a unique tamper-indicating sleeve which must be physically removed prior to removal of the closure member from the container.
The prior art has included a variety of press-on or snap-on types of closures which incorporate tamper-indicating features. The majority of these patents, however, include a separable tamperproof band formed as an integral part or extension of the container-engaging skirt portion of the closure. Examples of such prior art patents include U.S. Pat. Nos. 3,653,529 (Segmuller), 3,707,240 (Wilson) 3,913,771 (Acton, et al.), and 3,974,932 (Faulstich). One patent in the prior art which incorporates a separate tamperproof band which extends downwardly from the top panel of the closure in U.S. Pat. No. 4,029,231 (Jonsson). According to this latter patent, a tamperproof band, or tear-strip, is located alternatively in the transverse endwall or an outer sidewall of a protective cover which encloses an inner cap, or closure. Upon removal of the tamperproof band for purposes of gaining access to the inner cap, a major portion of the protective cover still remains to be removed and discarded. While such a structure may be effective as a tamperproof closure structure, it is not only somewhat inconvenient to open, but also represents a relatively uneconomical structure, since a major portion of the tamperproof closure is designed to be removed and discarded preparatory to gaining access to the reusable portion of the closure.